There are concerns regarding potential toxicity of certain phthalates. This causes an increasing pressure from public authorities and customers to shift towards the use of phthalate-free alternatives. Under this topic the REACH SVHC list is known where low phthalates like DEHP or DIBP are listed as reprotoxic agents, category 1B. This leads to the fact, that those substances could only be used with a specific authorisation after the sunset date of 21 Feb. 2015. So far they are not permitted in cosmetics (EU directive 2004/93/EC) and are forbidden in all toys (EU directive 2005/84/EC).
Additionally DINP, a commonly used plasticizer for synthetic roofing membranes, is said to cause cancer by the Californian government. So it can be assumed that the discussion about the health problematic of phthalates will not come to an end in the further future.
U.S. Pat No 2012/0214920 relates to a plasticizer composition comprising vicinally diacylated fatty acid esters derived from renewable feedstocks, and a process for a preparation thereof. A composition comprising a halogen-containing polymer and a plasticizer composition comprising the vicinally diacylated fatty acid esters is also described. A method for plasticizing halogen-containing polymers, such as polyvinyl chloride (PVC) resins is provided. The plasticizer compositions may be added to PVC resins in amounts ranging between 1 and 200 phr.
U.S. Pat No 2014/0235769 relates to processes for making a polyvinyl chloride dry blend composition with a phthalate-free, bio-based plasticizer and a filler, having a bulk density of greater than 0.67 g/cc and an extrusion rate of greater than 65 mg/minute for a single screw extruder of 0.75 in barrel diameter with a 25:1 L:D general purpose polyethylene screw at 75 rotations per minute screw speed, and compositions made by the processes are provided. Also the patent claims compositions with 20 to 80 wt % PVC, 10-40 wt % bio-based plasticizer and 5 to 40 wt % filler.
U.S. Pat No 2014/0309345 relates to plasticizer compositions comprising epoxidized fatty acid mono-esters and epoxy-esters. Furthermore the use of these compositions for usage in wire and cable jacketing and roofing membranes is claimed, too.
U.S. Pat No 2011/0272174 relates to PVC resin-based compositions that include biochemical plasticizers as the primary plasticizers. The compositions include PVC resin, a compatibilizer, one or more biochemical plasticizers and, optionally, a thermoplastic elastomer impact modifier. The biochemical plasticizers are present in substantial quantities in the compositions and, in some embodiments, are the only plasticizers present in the compositions. Furthermore it is claimed for compositions with 20 to 80 wt % PVC, 1 to 30 wt % compatibilizer and 5-60 wt % biochemical plasticizer. Also it is named that the biochemical plasticizer is based on an epoxidized derivative of vegetable oil or an additionally combination with an acetylated derivative of vegetable oil. These compositions could be used for cable jacketing or insulating layers.
U.S. Pat. No. 5,886,072 relates to flame retardant compositions for cable jacketing and wire insulation. The compositions consist of 100 parts PVC, 10-50 parts of an ester plasticizer that is the reaction product of a polyol consisting essentially of pentaerythritol and a mixture of fatty acids having an average carbon number of about 6.7, about 50-80 parts of aluminium trihydrate, no greater than 1-10 parts of brominated phthalate ester, about 2-20 parts of isodecyl diphenyl phosphate plasticizer, and 1-5 parts of zinc borate flame retardant, said composition being free of chlorinated polyvinyl chloride resin. Also another composition is named for cable jacketing ad wire insulation.
WO Pat No WO 2012/026861 relates to a plasticiser being an ester by reaction of a pentaerythrtiol and a monocarboxylic acid having 4-5 carbon atoms. In a further aspect the invention refers to the use in blends and in a PVC resin. The plasticiser is a non-phthalic plasticiser that has proven to have shorter fusion time and higher plasticising efficiency compared to commercial non-phthalic PVC plasticisers.
Nevertheless, these compositions are not especially developed for synthetic roofing membranes and do not comprise special ingredients for outside exposure. Here improvements in the UV stability, the ageing by high temperature (belonging to the colour of the membrane) and the resistance against microbiological attack of e.g. algaes has to be added to the composition to get a roofing membrane which could achieve long lifetime and withstand the conditions. Furthermore the ingredients have to fit the conditions of different temperature zones of the world. Also the stability against hydrolyses has to be guaranteed.